- Date
- May 20, 2011, 11:45 local (17:45 UTC)
- Place
- Colorado Springs, CO
- Injuries
- 1 serious
- Damage
- Substantial damage
- Phase of flight
- Initial climb
- Aircraft
- N566RLLammers Sjef J Apache
- Defining event
- Initial climb: Loss of control in flight
- Weather
- Visual (VMC) · Day
- Status
- Completed · report October 6, 2011
- Report
- Approved by Office Director
- NTSB office
- Central Region
- Parties
- FAA/FSDO
- Case key
- 79251
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
The pilot's failure to maintain control of the aircraft during take-off in a cross wind, which resulted in an inadvertent stall.
Findings · 2
NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.
Sequence of events
The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.
Analysis
On the morning of the accident, the pilot had removed his single-surface wing and installed a dual-surface wing on his weight shift aircraft. The winds were calm and he conducted an uneventful test flight. The pilot returned to his hangar and made some adjustments to the control bar but elected to not do another test flight because the winds were increasing at the airport. Later that afternoon, the pilot decided to do a second test flight because the wind had decreased some. The pilot departed with an 80 degree crosswind between 5 and 10 knots. He said that he did not build up sufficient airspeed on the takeoff roll and once he got airborne he was about 5 knots above stall speed and very slow. When the aircraft was approximately 100 feet in the air, he encountered wind shear and the right wing stalled and dropped. The pilot was unable to recover and the aircraft crashed on the right side of the runway, resulting in substantial damage to the entire aircraft.
Factual narrative
On the morning of the accident, the pilot had removed his single-surface wing and installed a dual-surface wing on his weight shift aircraft. The winds were calm and he conducted an uneventful test flight. The pilot returned to his hanger and made some adjustments to the control bar but elected to not do another test flight because the winds were increasing at the airport. Later that afternoon, the pilot decided to do a second test flight because the wind had decreased some. The pilot departed with an 80 degree crosswind between 5 and 10 knots. He said that he did not build up sufficient airspeed on the takeoff roll and once he got airborne he was about 5 knots above stall speed and very slow. When the aircraft was approximately 100 and 150 feet in the air, he encountered wind shear and the right wing stalled and dropped. The pilot was unable to recover and the aircraft crashed on the right side of the runway, resulting in substantial damage to the entire aircraft.
Aircraft
- Registration
- N566RL
- Reported as
- Lammers Sjef J Apache
- Category
- Weight-shift
- Serial number
- 12056
- Engine
- Rotax 582, 65 horsepower
- Damage
- Substantial damage
- Flight
- Personal · Part 91
- Operator
- Lammers Stef J
- Registered owner
- Lammers Stef J
- Airworthiness certificate
- Special, Experimental light sport (Special)
- Departed
- KFLY · Colorado Springs, CO
- Destination
- KFLY · Colorado Springs, CO
- Flight plan
- Unknown
- Airport
- KFLY · Meadow Lake, runway 15
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 55
- Certificate
- Sport Pilot
- Flight hours
- 340 total · 340 in this make and model
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 150° at 8 knots, gusting 14
- Visibility
- 10 statute miles
- Lowest ceiling
- 9,000 ft broken
- Temperature
- 50 °F, dew point 36 °F
- Altimeter
- 29.87 inHg
- Observed at
- KCOS, 10 nm away
Docket · 1
The files NTSB released with the investigation on July 15, 2011, on NTSB’s docket system: statements, records, photos and specialists’ reports. 73 KB in all.